KR20000071080A - Formazan Compounds and Method of Dyeing Therewith - Google Patents

Abstract

In dyeing (e.g., printing) cellulose fibers with a reactive dye, a good dye reproducibility is obtained, and a blue compound which gives a blue dye with excellent light fastness and chlorine water fastness and less contamination to white parts. This is strongly desired.

The present invention relates to a formazan compound represented by the following general formula (I) in the form of a free acid suitable for solving the above problems, a dyeing method for dyeing cellulose fibers using the same, and a resulting dye.

<Formula I>

(Wherein R represents hydrogen, sulfonic acid group, hydroxyl group, halogen, C ₁ -C ₄ alkyl group, C ₁ -C ₄ alkoxy group or carboxyl group, M represents copper or nickel, respectively)

Description

Formazan Compounds and Method of Dyeing Therewith}

In dyeing (cellulose printing) of cellulose fibers, reactive dyes are frequently used in terms of clarity of color, contamination to white portions, and fastness. Especially, the reactive dye which used the monochloro triazino group for the reactor is used suitably from the viewpoint of the outstanding time-lapse stability of a color paste. Specifically, as the yellow dye, C.I. As Reactive Orange 99, a red dye, C.I. As Reactive Red 3: 1, a blue dye, C.I. Reactive Blue 49, C.I.Reactive Blue 5, and the like.

The following quality characteristics are calculated | required for the reaction dye used for the printing of a cellulose fiber.

1) Good dyeing reproducibility is obtained by little condition dependence in intermediate drying after printing a color paste on a fiber. This is a characteristic derived from the affinity for the cellulose fibers of the dyes used. If the affinity of the dye is too low, the condition dependency in intermediate drying is large (when a relatively long time is required before drying, Dye transfer becomes large, and the color density of the printed fabric surface is lowered). Such dyes have a poor dye reproducibility which is dyed by a compound dye of yellow dye, red dye or blue dye between laboratory test and field processing.

2) It has little dependence on the steaming conditions (particularly the steaming time) of the reaction fixing process of the reactive dye, and thus obtains good dye reproducibility. This is a characteristic derived from the reactivity of the dye, and it is necessary to obtain a stable reaction fixation (concentration) even when the steaming conditions (steaming time) fluctuate with moderate reactivity. This property greatly influences the dye reproducibility in the field.

3) There is little contamination to white part (part where color paste is not printed), and high quality printing is possible.

4) It has excellent color fastness (especially light resistance and chlorine resistance) of printing materials, and long life of printing products.

Known blue dyes have serious drawbacks in terms of the quality properties required for such printing dyes. C.I. which is frequently used at present The anthraquinone-based blue dyes such as Reactive Blue 49 and CIReactive Blue 5 have a large dependence on the conditions of intermediate drying of 1) described above, and are poor in reproducibility of dyeing results in the laboratory and dyeing results in the field. Significantly reduce productivity. In addition, the fastness of the above-mentioned 4), in particular, chlorine resistance is remarkably poor, and there is a disadvantage that the color life of the product is short.

As a method for improving chlorine resistance and the like, Japanese Patent Publication No. Hei 5-21945 proposes a formazan blue dye, but the formazan compound described therein has a large steaming time dependency of 2) described above. Dyeing reproducibility in the field is poor, which also reduces productivity. In addition, there are a number of drawbacks such as poor contamination to the white part of the above-mentioned 3), which lowers the quality of the dyeing product due to printing.

It satisfies all of the quality characteristics of the above-mentioned 1) to 4) required for dyeing (especially printing) of cellulose fibers with reactive dyes, that is, it has little dependence on intermediate drying conditions and steaming conditions, and has excellent dye reproducibility, In addition, it is strongly desired to develop a blue dye that satisfies the contamination and chlorine resistance of the white portion, and improves the productivity of the printing process and enables high quality and long life of the product.

The present invention relates to a formazan compound and a method for dyeing fibers using the same. More specifically, the present invention is a method of staining cellulose fibers with little contamination in the white part, excellent in various fastnesses, especially light fastness and chlorine water fastness, and good dyeability (especially printing) with good reproducibility. It is about a method.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve the said subject, the formazan compound represented by following General formula (I) which has the 1-naphthylamino group substituted by the sulfonic acid group is remarkable also in any of said properties. The excellent thing was found and this invention was reached. That is, this invention relates to following (1)-(5).

(1) A formazan compound represented by the formula (I) in the form of a free acid.

(Wherein R represents hydrogen, sulfonic acid group, hydroxyl group, halogen, C ₁ -C ₄ alkyl group, C ₁ -C ₄ alkoxy group or carboxyl group, M represents copper or nickel, respectively)

(2) The formazan compound according to the above (1), wherein R is hydrogen and M is copper.

(3) A method for dyeing cellulose fibers, wherein the formazan compound according to (1) or (2) is used.

(4) The dyeing method according to the above (3), wherein the dyeing method is a printing method.

(5) Dyes dyed by the dyeing method described in (3) or (4) above.

(The best mode for carrying out the invention)

In the forazine compound represented by the formula (I) in the form of a free acid, specific examples of R include hydrogen, sulfonic acid group, hydroxyl group, chlorine, fluorine, bromine, methyl group, ethyl group, propyl group, n-butyl group and t-butyl A group, a methoxy group, an ethoxy group, a propoxy group, butoxy group, a carboxyl group, etc. are mentioned.

In order to obtain the formazan compound represented by the formula (I), a formazanamino compound represented by the formula (II) is first produced by the method described below.

(Wherein R and M represent the same meaning as described above)

That is, diazotized 6-acetylamino-2-aminophenol-4-sulfonic acid is represented by the formula (III).

In the formula, R represents the same meaning as described above.

Coupling to 5-sulfo-2-carboxyphenylhydrazones represented by the following, followed by the action of copper sulfate, nickel sulfate, copper chloride, nickel chloride and the like, and then hydrolyzing the acetylamino group with an amino group, A formazanamino compound is obtained.

Using the formazanamino compound thus obtained, formazan compound of formula (I) can be synthesized according to the method of (A) or (B) described below, for example.

(A) A formazanamino compound represented by formula (II) is reacted with 1 mole of 2,4,6-trichloro-1,3,5-triazine and is represented by formula (V) or formula (V) ' A condensate is obtained and then condensed with 1 mole of 1-naphthylamine-3,6,8-trisulfonic acid to give a formazan compound of formula (I).

(In addition, the formula (V) and the formula (V) 'is a mutant)

The reaction can be carried out in an inert solvent such as water. The reaction temperature is not particularly limited, but for example, the reaction between the formazanamino compound represented by the formula (II) and 2,4,6-trichloro-1,3,5-triazine is usually from about 0 deg. Condensation is carried out at about 15 ° C. for several hours at pH 2-7 until the unreacted compound of formula (II) disappears. Subsequently, the condensation of the compound represented by the formula (V) or the following formula (V) ′ with 1-naphthylamine-3,6,8-trisulfonic acid is, for example, about 15 ° C. to about 60 ° C., pH 1 to 7 hours until unreacted 1-naphthylamine-3,6,8-trisulfonic acid disappears.

(B) condensation of 1-naphthylamine-3,6,8-trisulfonic acid with 2,4,6-trichloro-1,3,5-triazine to obtain a compound of formula (VI) The formazanamino compound represented by the formula (II) is condensed with 1 mole of the compound represented by the following formula (VI).

These reactions are usually carried out in an inert solvent such as water, for example, 1-naphthylamine-3,6,8-trisulfonic acid and 2,4,6-trichloro-1,3,5-triazine; The reaction was condensed at 0 ° C. to 15 ° C. for several hours at pH 1 to 7 until 1-naphthylamine-3,6,8-trisulfonic acid disappeared, and the following formula (II) and formula ( The reaction with VI) is condensed, for example, at 15 ° C. to 60 ° C., pH 3 to 8 hours, until the unreacted compound of formula (II) disappears.

Since it is a little difficult to separate the target product by applying the usual separation method, such as salting method or acid stone method, the reaction solution is prepared as a liquid product or the reaction solution is desalted and concentrated. It is preferable to prepare a liquid product by adding a solubilizer or stabilizer such as alkanolamine, alkylamine, ε-caprolactam, and the like. Alternatively, the reaction solution may be spray dried as it is.

The formazan compound of formula (I) thus obtained exists in the form of a free acid or in the form of a salt thereof, and examples of the salt include alkali metal salts, alkaline earth metal salts, alkali amine salts, and alkanol amine salts. In particular, sodium salt, potassium salt, and lithium salt are preferable. In addition, each salt of the compound of the formula (I), after separating the target product in the form of free acid from the reaction solution, the compound is treated with an alkali agent to obtain the desired salt, or salt of the desired alkali agent as each raw material It is obtained by using.

The formazan compound represented by the formula (I) according to the present invention is natural cellulose such as cotton or hemp, regenerated cellulose such as rayon or polynosic, lyocell, and mixed fibers of these fibers with other fibers. It is suitable for dyeing and the like. As the dyeing method, in addition to the printing method and the padding dyeing method, a method used for dyeing by normal reactive dyeing such as a dyeing method can be applied. That is, if necessary, the dye composition comprising the formazan compound represented by the above formula (I) on the fiber or fabric in the presence of a dyeing aid or thickener, and dyeing by conventional methods such as dipping, printing or padding If necessary, fibers or fabrics can be dyed by fixing the dye by heat treatment such as heat drying, steaming, or dry heat treatment. Hereinafter, the representative method is described in more detail.

First, in the printing method, a color paste is prepared by adding a dye, urea, an acid binder, a reducing agent (for example, Polimine L New, Nippon Kayaku Co., Ltd.), etc. to raw material pastes such as sodium alginate and emulsion paste. This is printed on the fibers (stained water) and the fibers are subjected to intermediate drying (for example, 100 to 110 ° C for 2 to 3 minutes), followed by steaming treatment (for example, 100 to 103 ° C, 5-10 minutes) or dry to fix the dye thereon.

In addition, in the case of applying the compound of the present invention by padding dyeing (continuous dyeing), dyes, acid binders, penetrants (e.g., Succinol CHK, manufactured by Senka Co., Ltd.), urea as a dye dissolving agent, urea as a repair agent, transition A pad liquid made of sodium alginate or the like as an inhibitor is prepared, and the fibers are padded to perform intermediate drying (for example, 100 to 110 ° C for 2 to 3 minutes), followed by dry heat treatment (for example, 150 to 170). 2 minutes to 3 minutes), and the dye is fixed thereon.

As an example of the acid binder used in the above dyeing method, sodium hydrogencarbonate, sodium carbonate, trisodium phosphate, sodium metaphosphate, ortho- or meta-silicate silicate, sodium hydroxide, etc. are mentioned, for example.

When the formazan compound of the present invention is used in the printing method, in spite of fluctuations in intermediate drying conditions and fluctuations in steaming time, the color concentration variation is small, so that a stable color concentration is obtained, and the dye reproducibility is excellent. Moreover, there is little contamination to a white part and high quality printing material can be obtained. Moreover, in view of the relationship between the eutrophication phenomenon of the closed water area by nitrogen and phosphorus, the printing method which reduces nitrogen-containing urea is attracting attention recently. Although mass use of urea to provide adequate moisture to the fiber for the purpose of effectively reacting and fixing the reactive dye with the cellulose fiber has been indispensable until now, the printing degree in the method of reducing the urea by using the compound of the present invention It becomes possible. On the other hand, when the compound of the present invention is used in the padding dyeing method, there is also a feature that the difference in color between the start and end of the dyed fabric is small.

In addition, when the formazan compound of the present invention is used for the dyeing method in addition to the printing method and the padding dyeing method, similarly good results are obtained.

The dyeings of the present invention obtained by these dyeing methods are excellent in light fastness and chlorine water fastness, and have a fast and vivid blue color.

Moreover, even if it uses and mixes 2 or more types of compounds of this invention, and also mixes and uses the above-mentioned yellow dye, red dye, etc. which are currently used frequently, the same effect is acquired.

Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples. In addition, in an Example, "part" and "%" mean a weight part and weight%, respectively, The sulfonic acid group in each formula is represented by the free form.

Example 1

The synthesis | combination of the compound of this invention represented by following formula (i).

3.8 parts of cyanuric chloride were added under stirring to a solution consisting of 10 parts of water, 10 parts of ice, and 0.5 parts of 10% Liponox NA (trade name, dispersant, Lion Co., Ltd.) aqueous solution. After stirring for 30 minutes (suspension), a solution in which 7.7 parts of 1-naphthylamine-3,6,8-trisulfonic acid was dissolved in 20 parts of water was maintained over 30 minutes while maintaining the suspension at 10 ° C or lower. Thereafter, the mixture was stirred for 3 hours while maintaining the pH value at 2 to 4 with a 10% soda ash aqueous solution at around 10 ° C. The reaction solution was added to a solution in which 11.9 parts of the formazanamine compound of formula (VII) was dissolved in 100 parts of water.

The mixture was heated up and reacted for 3 hours while maintaining a pH value of 6-8 with a 10% soda ash aqueous solution at a temperature of 30-40 ° C. Further, 120 parts of a dye solution containing 18% of the compound of the formula (VII) was obtained by treating the reaction solution by desalting and concentrating (lambda max 610 nm in water).

Example 2

100 parts of color pastes were prepared by the composition ratio shown in the following table.

Compound of Example 1 (dye solution) 8 part Element 10 copies Sodium bicarbonate Part 2 Polymine L New (Note 1) 1.5 parts hot water 28.5 parts Raw Material Paste (Note 2) 50 copies system 100 parts

(Note 1) Polymine L New: A brand name, a reducing agent, Nippon Kayaku Co., Ltd. product.

(Note 2) Raw material paste: Snow Algin M (brand name) (sodium alginate type raw material paste which consists of 5 parts of sodium alginate type and 95 parts of water), product made by Fuji Chemical.

The above-mentioned raw material paste was printed on 50 g of mercerized cotton, and then intermediately dried at 100 ° C. for 3 minutes, and then steamed for 8 minutes in saturated steam at 100 ° C. to react and fix the dye.

Subsequently, after water washing and hot water washing, it soaps for 15 minutes using 1000 g of boiling water baths containing 2 g of Monogen (brand name, anionic surfactant, Daiichi Kogyo Seiyaku Co., Ltd. product). It washed again with water. The printed printing material was vivid blue, almost free from contamination on the white portion, and was excellent in light fastness and chlorine water fastness.

Examples 3-10

According to Examples 1 and 2, a compound was prepared, and dyeing (printing) of cotton was performed. Tables 2 to 4 show the structural formulas of the synthesized compounds, their color when dyed (printed), and lambda max in water of the compounds.

TABLE 2

TABLE 3

TABLE 4

Example 11

Using 5 parts of the compound of Example 1, rayon muslin printing was performed according to the printing method described in Example 2. The obtained dyeing thing showed the bright blue excellent in light and chlorine resistance. In addition, even when the steaming time was changed to 4 minutes, 8 minutes, and 16 minutes, the change in color density was insignificant.

Example 12

A pad liquid was prepared from 40 parts of the compound of Example 1, 20 parts of sodium carbonate, 150 parts of urea, 1 part of Snow Algin M (trade name) and 1000 parts of pure water, and 50 g of mercerized cotton broad was padded with a shrinkage of 70%, 100 3 minutes of intermediate drying was performed at ° C. Subsequently, the mercer processed cotton broad was subjected to dry heat treatment at 160 ° C. for 3 minutes, and the dye was reacted and fixed on the cotton broad. Thereafter, the cotton broad was washed with water, washed with water, and soaped for 15 minutes using 1000 g of a boiling water tank containing two parts of Monogen (trade name, anionic surfactant, Daiichi Kogyo Seiyaku Co., Ltd.), and washing with water again. It was.

The obtained dyeing thing showed bright blue excellent in light and chlorine resistance.

Comparison test

Compound of the present invention (Example 1) and five known dyes (CI Reactive Blue 49 as Comparative Example 1, Blue 5 as Comparative Example 2, Japanese Patent Application Laid-open No. 5-21945 Example 17, Comparative Example As Example 4 and Comparative Example 5, the quality comparison in the printing dyeing of the compound of each of Example 25 of the publication as Example 5 was performed according to the following method.

(A) common printing method

According to the composition shown in following Table 5, 100 parts of color pastes are prepared.

TABLE 5

Each compound (dye) X part Element 10 copies Sodium bicarbonate Part 2 Polymine L New (Note 1) 1.5 parts hot water 36.5-part X Raw Material Paste (Note 2) 50 copies system 100 parts

(Note 1) Polyimine L New: A brand name, a reducing agent, the Nippon Kayaku Co., Ltd. product.

(Note 2) Raw material paste: Snow Algin M (brand name) (sodium alginate type raw material paste which consists of 5 parts of sodium alginate type and 95 parts of water), product made by Fuji Chemical.

(Note 3) Since the usage-amount of a compound (dye) differs by each test of 4 items described after this, it was expressed generally here as X part. The usage-amount of the compound (dye) in each test was specifically described in the following (test conditions of each test item).

The color paste was printed on 50 parts of mercerized cotton, and then intermediately dried at 100 ° C for 3 minutes, and then steamed for 8 minutes in saturated steam at 100 ° C to react and fix the dye.

Subsequently, after washing with water and hot water, it was soaped for 15 minutes using 1000 parts of boiling water tanks containing 2 parts of anionic surfactants, and also washed with water.

(B) Test conditions of each test item

1) Medium drying condition dependence

4 parts of the compound of Example 1 (for the compounds of Comparative Examples 1 to 5, the same concentration as that of the compound of Example 1 is used for the optical density (OD) value) and C.I. Using 2 parts of Reactive Orange 99, dyeing was carried out in accordance with the above-mentioned (common printing method) except that the intermediate drying conditions were carried out at 2 levels of 3 minutes at 100 ° C and 1 hour at 40 ° C. Got water.

The color change on the surface side of the obtained printing material and the transition state of the dye to the back surface (degree of transfer of the dye to the back surface of the printing material) were visually determined, and the results are shown in Table 6. Evaluation criteria were according to the following criteria.

Comprehensive evaluation ○: The color of the surface (surface color) depends on the drying conditions

Is equivalent, and there is little dye transfer state to the back

Small (medium dependence on dry conditions; good condition)

X: The color (surface color) of the surface is in the drying conditions at the said 2 level.

As a result, the latter case clearly changes compared to the former case.

Was confirmed, and dye transfer state to the back was big, too

(High dependence on medium drying condition; poor condition)

2) Steaming time dependency (ST dependency)

Only 4 parts of the compound of Example 1 (for the compounds of Comparative Examples 1 to 5, the amount of the same concentration as the 4 parts of the compound of Example 1 is used as the OD value), and the steaming time is 2 minutes, 4 Except having changed into minutes, 8 minutes, and 16 minutes, it stained according to the former (common printing method) and obtained each printing material.

The reflectance of the obtained printing material was measured with a spectrophotometer CE-3100 manufactured by Macbeth, and Q-total value (optical density) was obtained. Table 6 shows the Q-total value ratio (optical concentration ratio) (QT value ratio) based on 8-minute steaming (100). Evaluation criteria of (circle) × followed the following criteria.

Evaluation ○: The QT value in any of steaming time 2 minutes, 4 minutes, and 16 minutes

The rain being over 80.

X: Steaming time 2 minutes, 4 minutes, 16 minutes, in any one of the QT

One or more containing a value ratio of 79 or less.

3) Contamination to white part (white part contaminant)

Except for using 8 parts of the compound of Example 1 (the amount of the compound having the same concentration as the 8 parts of the compound of Example 1 as the OD value for the compound of Comparative Examples 1 to 5) was used in the above (common printing method) In accordance with this, after the steaming treatment was performed, the following washing treatment was performed, and the contamination degree on the white portion (white cloth) at that time was determined to JIS L 0805 "Grayscale for pollution" based on the white cloth before washing.

Cleaning treatment

2.5 parts of printing (steaming) fabrics and 2.5 parts of mercerized cotton broad (white cloth) were placed in 100 parts of pure water and treated at 30 ° C for 10 minutes. Thereafter, the printing cloth and the white cloth were taken out and dehydrated, and the resultant was placed in 100 parts of fresh water again, treated at 90 ° C. for 10 minutes, and then dehydrated and dried.

The degree of contamination of the mercer processed cotton broad (white cloth) by this washing treatment was determined to JIS L 0805 "Grayscale for pollution" based on the white cloth. The result is shown in Table 6 by the judgment value and (circle) * evaluation. The higher the level, the better the judgment (less contamination).

In evaluation or (circle) or *, the judgment grade value showed 4 or more and (circle) and 3 or less as x.

4) Chlorine Water Color Fastness

6 parts of the compound of Example 1 (the amount of the compound having the same concentration as that of 6 parts of the compound of Example 1 is used as the OD value) for the compound of Comparative Examples 1 to 5, followed by the above (common printing method). The printing was carried out to obtain a printing material.

Using the obtained printed fabric, the chlorine-water fastness test was implemented according to JISL 0884 "chlorine-water fastness" steel test (effective chlorine 20 ppm). The result was shown in Table 6 by evaluation grade value and (circle), * evaluation. The higher the value of the judgment, the better (the less discoloration and fading).

The above test results are summarized in Table 6 and described.

As is clear from Table 6, C.I. Reactive Blue 49 (compound of Comparative Example 1) and Blue 5 (compound of Comparative Example 2) have a low affinity for the dye and are dried at a relatively low temperature (corresponding to drying conditions at the time of test dyeing). The dye transition of the pigment becomes large, the blue color of the surface decreases, and the color changes considerably yellow.

Therefore, reproducibility (particularly, reproducibility at the time of test dyeing and in situ processing) becomes poor. These dyes also have poor chlorine water fastnesses.

On the other hand, the compounds (dyes) described in Japanese Patent Application Laid-Open No. 5-21945 Examples 17, 19, and 25 have a large concentration change due to variation in the steaming time, and are highly reproducible (in this case, between field processing and steaming models). Liver reproducibility) is poor, and the contamination on the white part is also large and poor.

Only the compound of Example 1 had little intermediate drying condition dependence and steaming time dependence at the same time, stable color concentration was obtained, excellent dye reproducibility, and also excellent contaminant to white portion and chlorine water fastness at the same time.

Therefore, it was confirmed that the compound of this invention is a blue dye which achieves the productivity improvement of print processing, and the high quality and longevity of a product.

TABLE 6

Medium drying condition dependence ST dependency White part pollutant Chlorine Water Fastness compound Surface color State of transition of dye on the back Comprehensive Evaluation QT value ratio evaluation Judgment value evaluation Test value evaluation Compound of Example 1 equal Less ○ 94100 * (100) 99 ○ 4 ○ 3-4 ○ Compound of Comparative Example 1 Fairly yellow Dye transition big to blue back side × 8394 * (100) 100 ○ 4-5 ○ 1-2 × Compound of Comparative Example 2 Fairly yellow Dye transition big to blue back side × 8595 * (100) 99 ○ 4-5 ○ 2 × Compound of Comparative Example 3 equal Less ○ 106101 * (100) 73 × 2-3 × 3-4 ○ Compound of Comparative Example 4 equal Less ○ 107101 * (100) 72 × 2-3 × 4 ○ Compound of Comparative Example 5 equal Less ○ 6890 * (100) 98 × 2-3 × 4 ○

(Note) Supplementary explanation of each item of table 6

(1) Intermediate drying condition dependence: 40 ℃ 1 on the basis of the drying of 100 ℃ 3 minutes 1

The color of the dry matter of time and dye on the back

Row status

(2) ST dependence: The QT value ratio was obtained at steaming time of 2 minutes, 4 minutes and 16 minutes.

The Q-total value is expressed as 8 minutes of steaming time (* (100) in the table).

C)% of the Q-total value (reference), from 2 above

Minutes, 4 minutes, and 16 minutes in that order.

(3) White Partial Pollution: Judgment value is according to JIS L 0805 "Grayske for Contamination"

Value ".

(4) The grade was based on the test value of chlorine water fastness according to the high concentration test (20 ppm of effective chlorine) of chlorine water fastness of JIS L 0884.

(5) Compound of Comparative Example 1: C.I. Reactive Blue 49

(6) Compound of Comparative Example 2: C.I. Reactive Blue 5

(7) Compound of Comparative Example 3: Compound of Example 17 of JP-A 5-21945

(8) Compound of Comparative Example 4: Compound of Example 19 of JP-A 5-21945

(9) Compound of Comparative Example 5: Compound of Example 25 of JP-A 5-21945

The compound of the present invention is capable of dyeing cellulosic fibers with good reproducibility and bright blue color, and the dyeing material is characterized by excellent light fastness and chlorine water fastness and little contamination on white parts. Therefore, the dye of the present invention is greatly useful for improving the productivity of dyeing processing, and is used for producing high-quality, long-life excellent dyeing products.

Claims (5)

A formazan compound represented by formula (I) in the form of a free acid. <Formula I> (Wherein R represents a hydrogen, a sulfonic acid group, a hydroxyl group, a halogen, a C ₁ -C ₄ alkyl group, a C ₁ -C ₄ alkoxy group or a carboxyl group, and M represents copper or nickel, respectively) The formazan compound according to claim 1, wherein R is hydrogen and M is copper. Method for dyeing cellulose fibers, characterized in that formazan compound according to claim 1 or 2. The dyeing method according to claim 3, wherein the dyeing method is a printing method. Dyes dyed by the dyeing method according to claim 3.